To rapidly fill containers, such as the fuel tanks on mobile equipment, liquids are pumped under pressure into the containers. Given the size of fuel tanks on heavy equipment, such as mining equipment, high pressures are used to reduce filling times. A supply hose, connected to the outlet of a pressure pump, is usually provided with a flow nozzle releasably connectable to a flow coupling on the container. The flow nozzles are usually provided with shut-off valves to stop the flow of liquid to the container when back pressure indicates that the container is full. However, operators often manually override these shut-off valves, since it is common for the shut-off valves to “trip” before a container is full. With large equipment, such as mining equipment, operators have manually overridden shut-off valves; pressure can build to the extent that fuel tanks bulge, and even rupture. Clearly, the damage to the tanks, and the loss of fuel, is unacceptable.
One attempt to address this issue resulted in the flow control valve assembly disclosed in U.S. Pat. No. 6,311,723 to Shipp et al. In use, the Shipp type of device was often installed directly in the side of a tank. The piston-containing chamber extended out into the tank and the sidewall ports disposed at a distal point along the axis thereof would act as opposite directional nozzles, resulting in turbulence in the tank, and often further resulting in premature shutoff. This design also utilized the sidewall of the piston to effect closure of the ports, often without a positive stop for the piston, other than the length of the spring. During motion of the equipment, the piston could be unseated. Additionally, the lever-style float valve was found to lack sufficient durability, due to fluid motion in the tank.
Clearly, there is a need for apparatus or systems that prevent overfilling while resolving some of the problems found in the prior art devices.